org.apache.marmotta.kiwi.persistence.registry

Class DBTripleRegistry

java.lang.Object

org.apache.marmotta.kiwi.persistence.registry.DBTripleRegistry

All Implemented Interfaces:

KiWiTripleRegistry

public class DBTripleRegistry
extends Object
implements KiWiTripleRegistry

This class is used for keeping triples that are used by several transactions in parallel in sync. It allows a transaction that creates a triple to register this triple and make the triple ID available to other transactions to avoid duplicates. When a transaction commits, it then releases all its triple registrations.

The implementation is based on a very simple database table (REGISTRY). When a transaction creates a triple with a new ID, it temporarily inserts a row mapping the (subject,predicate,object,context) -> triple ID. Other transactions trying to create the same triple can then first lookup this ID. If they do so successfully, they will also insert a row to the registry.

Author:

Sebastian Schaffert (sschaffert@apache.org)

Constructor Summary

Constructors

Constructor and Description
DBTripleRegistry(KiWiStore store)

Method Summary

Methods

Modifier and Type	Method and Description
protected KiWiConnection	aqcuireConnection()
void	deleteKey(IntArray key) Remove the key with the given key, e.g.
long	lookupKey(IntArray key) Check if another (or the same) transaction has already registered an ID for the triple with the given key.
void	registerKey(IntArray key, long transactionId, long tripleId) Register a key/triple id pair in the triple registry for the given transaction ID.
protected void	releaseConnection(KiWiConnection con)
void	releaseTransaction(long transactionId) Free all registry entries claimed by the transaction with the given identifier.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

DBTripleRegistry

public DBTripleRegistry(KiWiStore store)

Method Detail

registerKey

public void registerKey(IntArray key,
               long transactionId,
               long tripleId)

Description copied from interface: KiWiTripleRegistry

Register a key/triple id pair in the triple registry for the given transaction ID.

Specified by:

registerKey in interface KiWiTripleRegistry

Parameters:

key - the key identifying the triple arguments (subject, object, predicate, context)

transactionId - the identifier of the transaction registering the triple id

tripleId - the new triple identifier

lookupKey

public long lookupKey(IntArray key)

Description copied from interface: KiWiTripleRegistry

Check if another (or the same) transaction has already registered an ID for the triple with the given key. Returns -1 in case no other ID has been registered, or a value >0 otherwise.

Specified by:

lookupKey in interface KiWiTripleRegistry

Parameters:

key - the key identifying the triple arguments (subject, object, predicate, context)

Returns:

id of the triple or -1

releaseTransaction

public void releaseTransaction(long transactionId)

Description copied from interface: KiWiTripleRegistry

Free all registry entries claimed by the transaction with the given identifier. Should remove or expire all registry entries to avoid unnecessary storage consumption.

Specified by:

releaseTransaction in interface KiWiTripleRegistry

Parameters:

transactionId - the identifier of the transaction registering the triple id

deleteKey

public void deleteKey(IntArray key)

Description copied from interface: KiWiTripleRegistry

Remove the key with the given key, e.g. when a statement is again deleted during a transaction.

Specified by:

deleteKey in interface KiWiTripleRegistry

Parameters:

key - the key identifying the triple arguments (subject, object, predicate, context)

aqcuireConnection

protected KiWiConnection aqcuireConnection()

releaseConnection

protected void releaseConnection(KiWiConnection con)